What's the deal with Brisbane tap water?

Every state likes to brag about their local drop, but how does Brisbane tap water compare to the rest of the nation? We’ll be focusing on South East Queensland Water, Seqwater, and Urban Utilities, who are the major players in Brisbane’s water supply and distribution.

Where does Brisbane drinking water come from?

Seqwater is the region’s bulk water supplier that provides nearly 150,000 megalitres (ML) of drinking water alone in South East Queensland. This drinking water comes from 107 reservoirs and is delivered through 9,500 km of water mains.

Urban Utilities, Brisbane’s water service provider, supplies 136,000 ML of water in total to its service area – that’s over 50,000 Olympic-sized swimming pools!

50% of Brisbane’s drinking water comes from Wivenhoe dam, according to Mike Foster from Seqwater. If filled to capacity, this dam can hold 1.165 million megalitres of water!

After the major impact of the Millenium drought in the 2000s, Seqwater implemented a water grid. This allows the transport of treated water to areas that need it most to help bolster their water supply in times of need.

The desalination plant in the Gold Coast acts as a backup source of water for the water grid. The plant can supply 133 ML of water per day at full capacity.

If drought conditions push dam levels below 40%, recycled water also comes into play. In combination with recycled water from the Western Corridor Recycled Water Scheme, this accounts for over a third of the entire region’s water demands.

The Facts About Water Treatment Brisbane

Water from Wivenhoe Dam is sent to the Mount Crosby water treatment plant. Raw water is treated so it is safe to drink and delivered to homes around Brisbane.

When the water arrives at the treatment plant, it contains soil, pollutants, debris, microorganisms and more that need to be removed. To be considered safe to drink, the water must meet Australian Drinking Water Guidelines.

A thorough treatment process at Mount Crosby follows a number of water treatment steps.

Coagulation

A coagulant is added to the raw water, typically aluminium sulphate. The water is mixed and reacts with the coagulant to form a thickened mass of particles.

The water pH must be between 6.8 and 7.2 for the next step and so the treatment plant tests and adjusts the pH here.

Raw water at the Mount Crosby treatment plant is often very turbid, making this step essential in the treatment process.

Flocculation and Sedimentation

The mass of particles formed during the coagulation step forms a floc. These clump together and form heavier masses.

The raw water and floc move into two sedimentation basins. The floc particles bind together and form a sludge that sinks to form a sediment on the bottom of the basin floor.

Workers regularly vacuum the floor to remove the sediment and transport it to a waste sludge pool.

Filtration

With the sludge removed, the water treatment plant filters the water. Mount Crosby starts with dissolved air filtration – a process where they inject a pressurised stream of water containing oxygen, causing bubbles to rise up from the floor.

Floc particles attach to these bubbles and float to the surface to form a floating sludge blanket. This is regularly removed, leaving behind clarified water. While this water might look just like what comes out of our tap, it still has two more steps before it meets drinking water quality guidelines.

Disinfection and pH Correction

Before any water leaves the Mount Crosby water treatment plant, it undergoes disinfection and pH correction:

• Chlorine kills microorganisms, bacteria and viruses
• Lime corrects the pH for human consumption and prevents corroding or rusting the pipes during transportation
• Fluoride is added as a dental health measure

They pump this water to reservoirs at Cameron’s Hill and add chloramine to prevent harmful microorganisms from growing while they transport the water to Brisbane residents.

Brisbane Water Quality Tests

Australia has a strict set of regulations for drinking water – the Australian Drinking Water Guidelines. These guidelines are regularly updated to meet the most up-to-date scientific evidence available.

The authorities check for safe levels of:

• Arsenic
• Chlorine
• Fluoride
• lead
• Nickel
• Trihalomethanes

The aesthetic categories include:

• Colour
• pH
• Temperature
• Total dissolved solids
• Total hardness
• Turbidity

These guidelines were devised with Australian residents’ health in mind, and while not mandatory, most water suppliers and providers follow them.

Is tap water in Brisbane safe to drink?

Yes – tap water in Brisbane is perfectly safe to drink and meets all the Australian Drinking Water Guidelines. 2019/20 had 33% fewer water quality complaints than 2018/19!

Seqwater and Urban Utilities are committed to providing Brisbane residents with high-quality, safe drinking water. Across the whole South East Queensland region, Seqwater carried out over 112,000 tests with over 11,400 samples in 2019/20 alone to ensure good drinking water quality.

Any anomalies outside of these guidelines are actioned immediately and tested to assess the safety of the water. Brisbane’s water quality is only on the way up, with water authorities also future-proofing supplies with alternative water supplies such as recycled water.

If Brisbane tap water still concerns you, you can install a water filter that will ensure the water you are drinking is clean.

Wonder how Brisbane’s tap water compares to other capital cities? We’ve also put Perth, Melbourne and Adelaide tap water to the test!